Polyester-vinyl monomer compositions containing amidino compound and a sulfhydryl compound and process for copolymerizing same



United States Patent POLYESTER-VINYL MONOMER COMPOSITIONS CONTAININGAMIDINO COMPOUND AND A SULFHYDRYL COMPOUND AND PROCESS FORCOPOLYMERIZING SAME No Drawing. Application January 23, 1957 Serial No.635,578

17 Claims. (Cl. 260-454) This invention relates to unsaturated polyesterresin While these resins have many excellent characteristics,

their gelation and cure are rather slow even at elevated temperatures.By the use of some promoting agents, curing can be accomplished at roomtemperature with organic peroxide polymerization catalysts, but theseparticular promoters usually discolor the resin. There is a definiteneed for faster gelling resins of this class, which may be cured at roomtemperature without discoloration. An object of this invention is toprovide improved unsaturated polyester resin compositions.

Another object of this invention is to provide improved procedures forpromoting the polymerization of unsaturated polyester resin compositionsin general.

A further object of this invention is to provide unsatu rated polyestercompositions which gel more rapidly.

Still another object of the invention is to provide unsaturated linearpolyester compositions which may be cured at room temperature tosubstantially colorless masses.

A still further object of the invention is to provide a faster curingcycle for polyester resins.

Still another object of the invention is to provide a con- Thesecomprise essentially a trollable polymerization cycle for unsaturatedpolyester In order to efiect cure of a thermosetting polyester resin,heat is usually applied to expedite the polymerization reaction. Whenpolymerization of the mixture is carried out at elevated temperatures,the exothermic heat of reaction may be so great that the attendantstresses and strains developed therefrom often result in cured productswhich are cracked or badly crazed. It is desirable to efiect a rapidgelation of the polymerizable mixture, if possible, and then carry outthe final cure of the material over an extended period of time. While noactual saving in the amount of heat required to effect cure would berealized thereby, nevertheless, the danger of generating an excessiveexothermic heat would be alleviated by gelling the resin at a lowertemperature and in a reduced period of time. Final cure could then becarried out without the danger of the material cracking or crazing. Thepresent invention is concerned with unsaturated polyesterresincompositions and the process oi polymerizing these resins. Thenovel resins comprise one or more unsaturated linear polyesters, one ormore copolymerizice 7 Patented Feb. 4, 1958 group and tautomers thereof.The term amidino compounds is employed herein for brevity in describingthe class of unsubstituted and substituted amidines containing saidbasic group .and their tautomers, including the acid salts of any ofthese substances. Narrower aspects of the invention relate to selectedamidino compounds and specific proportions of the promoter combination.

The major components of the resin compositions are an unsaturated linearpolyester derived from a polyhydric alcohol and an olefinic or ethylenicunsaturated polycarboxylic acid and also a monomer having a terminalethylenic group which is copolymerizable with that polyester.

Among the many suitable polyhydric alcohols are ethylene glycol,diethylene glycol, propylene glycol, dipro pylene glycol, trimethyleneglycol, tetramethylene glycol, pinacol, arabitol, xylitol, dulcitol,adonitol, mannitol, glycerol, trimethylol propane, trimethylol ethane,sorbitol, l,l'-isopropylidene bis( p phenylenoxy)di 2 propanol,pentaerythritol, dipentaerythritol, and alkanediols as exemplified bybutanediol-l,2, butanediol-1,3, butanediol- 1,4, pentanedioll,2,pentanediol- 1,4, pentanediol 1,5, hexanediol-1,6, and the like. It isusually desirable that a dihydric alcohol be employed in majorproportion relative to any alcohols containing more than two hydroxygroups which may be used in forming the polyester. 'Another essentialreactant in forming the present un saturated alkyds is a polycarboxylicacid. The expressions polycarboxylic acids and dicarboxylic acids? areused herein in their broader sense toinclude available similarlyreacting anhydrides such as maleic and phthalic anhydrides. Among thesuitable alpha, beta-ethylenically unsaturated acids are maleic,funiaric, aconitic, itaconic, citraconic, mesaconic, chloromaleic,carbic, etc., acids, and mixtures thereof. Substantial amounts, ofpolycarboxylic acidswhich are free of non-benzenoid unsaturation mayalso be used, but the unsaturated acids should be present in an amountapproximating at least 5%. by weight of the total weight of thepolycarboxylic acids used. Frequently the olefinic or ethylenicallyunsaturated acids amount to between about 25% and 65% by weight on thesame basis. Examples of polycarboxylic acids which are free ofnon-benzenoid unsaturation include phthalic, oxalic, malonic, succinic,glutaric, sebacic, adipic, pimelic, suberic, azelaic, tricarballylic,citric, tartaric and malic acids, and mixtures thereof.

In the preparation of the polymerizable unsaturated polyesters, one mayuse the polyhydric alcohols andthe polycarboxylic acids in substantiallyequiniolar proportions;.but an excessofthe alcohol approximating 10 or15% above the stoichiometric quantity required for com: pleteesterification of the acid is preferred. Where a polyhydricalcoholcontaining .more than two hydroxy groups or a polycarboxylicacid havingmore than two carboxyl groups is used, the proportions of reactantsshouldbe adjusted accordingly to provide for esterification of theseadditional reactive groups. The alcohol and acid should be reactedsufficiently to produce an ultimate polyester resinous material havinganacid number not greater than about 55 and usually an acid number fromabout 35 to about 40 for most purposes. 7

The well-known thermosettingunsaturated polyester resins and theirpreparation are disclosed in detail in U. S. Patents Nos. 2,255,313,2,632,751 and 2,443,735 to,

, 2,443,741, inclusive, which ;are incorporated hereiuby refer nce In adion to the unsatu ated. alkyd esins, these compositions typicallycontain a monomeric crosslinking agent such as styrene or diallylphthalate. The unsaturated polyester content may, range tromabout 10 toabout 90% of the total weight of; copolymerizablematerial depending onthe particular qualities, desired in the final resin. For the majorityof purposes, it is recommended that about 60 to about 80 parts by weightof the unsaturated alkyd resin be dissolved in 40 to 20 parts ofpolymerizable monomer.

The cross-linking component of the new compositions comprises one ormore liquid monomers containing a 'CH =C group and having a meltingpoint belowabout 15 C. and a boiling point above about 60 C. Among themyriad of suitable terminal ethylenic comonomers are: styrene, styreneswith alkyl and halogen substituents on the ring and side chain such asmand p-methyl styrenes, alpha methyl styrene, 2,4-dimethyl styrene. 2.3-dimethyl styrene, 2,5-dimethyl styrene, alpha chlorosty rene, alphaethyl styrene, p-ethylstyrene, m-propyl styrene, bromostyrene,dichlorostyrene, isopropenyl toluene, vinyl naphthalene, and the 0-,mand p-chlorostyrenes and brornostyrenes; esters of alpha-methylenealiphatic monocarboxylic acids, such as methyl acrylate, ethyl acrylate,n-butyl acrylate, isobutyl acrylate, .dodecyl acrylate, 2-chlorethylacrylate, Z-chioropropyl acrylate, 2,2'-dichloris opropyl acrylate,phenyl acrylate, cyclohexyl acrylate, methyl alpha-chloroacrylate,methyl methacrylate, ethyl methacrylate, methylethacrylate;acrylonitrile, methacrylonitrile; vinyl esters, such asvinyl acetate, vinyl chloroacetate, vinyl propionate, vinyl butyrate,vinyl laurate, vinyl stearate; vinyl ethers such as vinyl methyl ether,vinyl isobutyl ether, vinyl 2-chlorethyl ether; vinyl ketones, such asvinyl methyl ketone, vinyl hexyl ketone, methyl isopropenyl ketone;isobutylene', vinylidene halides, such as vinylidene chloride,vinylidene chlorofiuoride; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl succinimide; acrolein,methacrolein, acrylamide, methacrylamide, N- methylol acrylamide; andallyl compounds such as diallyl phthalate, tetrachlorodiallyl phthalate,allyl alcohol, methallyl alcohol, allyl acetate, allyl methacrylate,diallyl carbonate, allyl lactate, allyl alphahydroxyisobutyrate, allyltrichlorosilane, allyl acrylate, diallyl malonate, diallyl oxalate,diallyl gluconate, diallyl methylgluconate, diallyl adipate, diallylsebaeate, diallyl citraconate, the diallyl ester of muconic acid,diallyl itaconate, diallyl chlorophthtalate, diallyl dichlorosilane, thediallyl ester of -endomethylene tetrahydrophthalic anhydride, triallyltricarballylate, triallyl aconitate, triallyl citrate, triallylcyanurate, triallyl phosphate, trimethallyl phosphate, tetraallylsilane, tetraallyl silicate, hexallyl disiloxane, andthe like.

The presence of a catalyst is usually desirable to eifect thepolymerization of the unsaturated polyester resin and; the monomericmaterial containing the polymerizable CH ;C group. Catalysis of thewell-known peroxide class are preferred. The amount of the catalystemployed may vary over rather wide limits to give varying catalyzedstability. Thus, from about 0.1% to about by weight, based on the totalweight of the polymerizable composition, may be used. Preferably, fromabout 0.2 to about 2% by weight of the catalyst, based on the totalweight of the polymerizable resinous composition, gives the desiredresults. A faster rate of cure usually results from increasing thecatalyst content within the aforementioned limits. A few examples of themany suitable organic peroxide catalysts are benzoyl peroxide, succinylperoxide, acetyl peroxide, methyl ethyl ketone peroxide, ditertiarybutyl peroxide, cumene hydroperoxide, tertiary butyl hydroperoxide,cyclohexanone peroxide, perbenzoic acid, peracetic acid, anisoylperoxide, toluyl peroxide, p-brornobenzoyl peroxide, tertiary butylperben zoate, prnenthane hydroperoxide, pinane hydroperoxide,diisopropylbenzene hydroperoxide, tertiary butyl peracetate,

l cyclohexanol-l-hydroperoxide, furoyl peroxide and chloracetyl peroxideor any organic ozonide, such. as diisopropylene ozonide, diisobutyleneozonide or a mixture of such substances may be used as the curingcatalyst. Other free radical type polymerization catalysts that may alsobe used are such as m,aazodiisobutyronitrile, the saltsof inorganicper-acids, e. ,g., ammonium persultate, sodium persulfate. and the like.

'It-isadvantageous to add a moderate amount of an inhibiting agent tothe composition to increase the storage stability to the uncatalyzedmixture. Examples of in hibiting agents that may be used in my inventionare such as hydroquinone, ditertiary butyl hydroquinone,pyrogallol,-tannic acid, tertiary butyl catechol, di-tert-butylp-cresolor an organic amine such as aniline or phenylene diamine. Mixtures of.the inhibiting agents may also be used if desired. About 0.004% to about0.02% of inhibiting agent by. weight, based on the total weight of theresinous composition, usually gives satisfactory results.

The desirable and controllable curing cycle of the resinous compositionof my invention is obtained by the addition to the polymerizable mixtureof a small but effective amountof a promoter system for the catalyst Thepromoter system employed comprises an amidino compound in combinationwith a mercaptan or sulfhydryl compound. A synergistic effect in theform of rapid gelation is obtained with this combination as is apparentfrom a comparison of the illustrative examples with the comparativeexamples in the table below. In addition to this unpredictable efiect ofgreatly speeding up the polymerization of unsaturated polyester resins,another unexpected advantage has also been discovered in that manyperoxide catalysts for these resins are operative at room temperaturewith the new promoter system whereas elevated temperatures are requiredin using them with certain other well-known promoters like cobaltnaphthenate.

Any one or more of a wide variety of mercaptans or sulfhydryl compoundsmay be used in the present compositions. Aliphatic, aromatic andcycloaliphatic mercaptans are suitable agents, and they may have otherfunctional groups in addition to the thiol radical as exemplified by thecarboxyl group in thioglycollic acid. A partial list of suitablesulfhydryl compounds includes: sodium hydrosulfide, n-hexyl mercaptan,n-heptyl mercaptan, n-octyl mercaptan, n-nonyl mercaptan, n-decylmercaptan, n-undecyl mercaptan, n-dodecyl mercaptan, ntridecylmercaptan, n-tetrodecyl mercaptan, n-hexadecyl mercaptan, secondaryhexyl mercaptan, tert-hexyl mercaptan, tert-octyl mercaptan,mercaptoacetic acid, thioacetic acid, p-toluenethiol, p-mercapto-phenol,2-mercaptobenzoic acid, 4-mercaptoquinazoline, thio-u-toluamide,thioacetamide thioacetanilide, Z-naphthalenethiol, cysteinehydrochloride, trithiocyanuric acid, thiohydrantoin, thiobarbituricacid, cyclohexyl mercaptan, calcium and ammonium hydrosulfides, and evengaseous hydrogen sulfide. While from about 0.001 to about 1.0% of theselected sulfhydryl compound may be used based on the total weight ofunsaturated alkyd and. copolymerizable monorner in the resinouscomposition, quantities ranging from abopt 0.005 to about 0.15% arerecommended for purposes,

There isalsoa large number'of substances which may be chosen as theamidino component of the promoter system. Any one or more. compoundsboiling above about 60 C. and containing a basic group or tautomersthereof or acid salts of either may be used. These amidinesor guanylcompounds may be either unsubtituted or substituted with a wide varietyof aromatic, aliphatic or cycloaliphatic radicals. While this ingredientof the promoter combinationmay be em p c edl fliout msd fis t onr t setn esi a e to, util ze the acid salt form of the amidino compound becausebasic compounds are apt to reduce or destroy the ultraviolet lightabsorbing power of certain hydroxylated benzophenones. Many differentorganic and inorganic acids are suitable for preparing these amidinosalts; for instance hydrochloric, hydrobromic, sulfuric, nitric,phosphoric, carbonic, acetic, formic and the like acids.

Examples of organic compounds and the salts thereof containing the basicgroup which may be employed in the resinous compositions of theinvention are the guanidines, e. g., dicyclohexyl guanidine,1,2-diphenyl guanidine, diphenyl-p-tolylguanidine hydrochloride,di-o-tolylguanidine, 1,3-dixylylguanidine, dodecylguanidine,1,3-bis(2-chloro-4-methoxyphenyl) guanidine hydrobromide, guanidinehydrochloride, ethylene guanidine hydrochloride, 1,1'-(ethylenedip-phenylene)dig1anidine hydrochloride,1-ethyl-2,3,4-triphenylguanidine hydrochloride, p-hydroxybenzylguanidine, methoxyguanidine sulfate, N,N-dicyclohexylguanidine,butyldicyclohexyl guanidine bicarbonate, octylguanidine nitrate; theisomelamines, e. g., 1,3,5-tribenzylisomelamines, triphenylisomelamines;the amidines, e. g., acetamidine, benzamidine, laurylamidinehydrochloride, dodecylamidine hydrochloride, acetamidine hydrochloride;the biguanides, e. g., phenylbiguanide hydrochloride, isopropylbiguanidehydrochloride,l,1-bis(2-hydroxyethyl)-3,5-bis(3-methoxypropyl)-biguanide acetate,l-(p-bromophenyl)-biguanide hydrochloride, p-chlorophenyl biguanide; thebiguanidines, e. g., (3-dibenzofuryl)methylbiguanidine,l-(p-iodophenyl)biguanidine hydrochloride, (p-methoxyphenyl)sulfanilylbiguanidine, o-tolylbiguanidine,l-(p-chlorophenyl)-5-isopropylbiguanidine,1-(2-dibenzofuryl)biguanidine, phenylbiguanidine hydrochloride,isopropylbiguanidine hydrochloride; the guanylureas, e. g.,guanyl(phenylsulfonyl) guanylurea, 1-guanyl-2-thioguanylurea carbonate,heptylguanylurea, l-hexyl-l-methylguanylurea, (Z-hydroxyethyl)guanylurea, l-(alpha-hydroxybutyryl)guanylurea; the pseudoureas orisoureas and their tautomers, e. g., 2-(7-chloro-4-methyl-2-guinolyl)-2-thiopseudourea hydrochloride, Z-p-cyanobenzyl-Z-thiopseudoureahydrochloride, Z-cyclohexylpseudourea, 2-decylpseudeourea,ethylpseudourea, 2-dodecylpseudourea hydrochloride,2-(dodecyloxymethyl)-2-thiopseudourea hydrochloride, laurylpseudoureahydrochloride, dimethylallyl pseudourea; the pseudothioureas and theirtautomers, e. g., ethylpseudothiourea and the ethyl pseudothioureahydrobromides; and the like.

Based on the content of active material, that is omitting the weight ofany acid component, the amidino compound desirably amounts to betweenabout 0.0003 and about 0.5% of the total weight of unsaturated alkydresin and cross-linking monomer, 0.001 to 0.1% being preferred for mostpurposes. While larger quantities may often be utilized, increasing theconcentration of this component beyond the stated range impairs theaccelerating effect of the promoter combination in some cases. Theconventional additives of the prior polyester resin art in the usualquantities are adaptable to use with the novel copolymerizable mixturesand polymerization products of the present invention. Many of these aredisclosed in the aforementioned U. S. patents and thus need not be setforth here in detail except to mention that such additives include otherpromoters for use in conjunction with the catalyst for curing at room orlower temperatures; mold lubricants; fire-retardant agents includingcompounds containing chlorine and phosphorus; fillers and reinforcementslike ground asbestos and glass fibers; inhibitors, like hydroquinone, tostabilize the resin mixtures against premature gelation; colorants suchas compatible dyes and pigments; and plasticizers.

As an optional ingredient of the new resin formulations, an ultravioletlight absorbing agent may be included in an amount ranging from about0.05 to about 3.0%

or more based on the total weight of polymerizable mat ter, 0.2 to 1.0%being preferred, to eliminate or minimize yellowing in the case oflight-transmitting or light-colored products. This additive isunnecessary for dark resin formulations. The class of hydroxylatedbenzophenones, including those containing other substituents, isespecially recommended since this group of compounds does not undergoany color change upon absorbing ultraviolet radiation. A few of the manysuitable agents are 2,2-dihydroxy-4-methoxybenzophenone,2,2-dihydroxy-4,4'-dimethoxybenzophenone, 2 hydroxy 4methoxybenzophenone, 2 hydroxy 4' methoxybenzophenone, 2 hydroxy 4,4dimethoxybenzophenone, 2,4 dihydroxybenzophenone, 2 hydroxy 5salicylylbenzophenone, and like compounds.

Curing of any of the new liquid resin compositions may be accomplishedwith or without added pressure in the atmosphere or in closed molds attemperatures ranging from about 10 C. up to 150 C. or even highertemperatures as long as they are kept below the point at which resindegradation commences. Where convenient, it is often desirable to formthe copolymers by heating the catalyzed resin-forming mass to betweenand about C. for a period of about 10 to 90 minutes to expediteproduction.

The components of the novel promoter system is introduced into theresinous composition prior to the gelation thereof. Since certainmercaptans tend to reduce the storage life of the resin compositions, itis sometimes desirable to add this component a few htours or few daysbefore the resin is used. Both ingredients of the promoler system can beincorporated in the resin compositions by simply mixing them with theother components, but it is often desirable to add them as solutions insuitable liquids in order to insure the uniform dispersal of the smallquantities of these compounds throughout the large mass of the resin. Inaddition, it is a simpler matter to measure a quantity of a minoradditive by measur-' ing the volume of a solution then by weighing asolid. For example, the amidino compound may be dissolved in apolyhydric alcohol such as diethylene glycol and added as a 10% solutionto the resin composition While the sulfhydryl compound may be similarlyadded as a 10% solution in styrene. It is customary to add thepolymerization catalyst to the resin composition last inasmuch as only alimited amount of time for mixing remains after the catalyst has beenincorporated in the resin before gelation occurs.

The novel cured resins possess the excellent and wellknown qualities ofpolyester resins in general. During their polymerization, no gases areevolved in the curing operation. Since water-white, transparent productsare obtainable, they, of course, may be dyed or pigmented in a limitlessvariety of shades and hues. In view of their good physical properties,the new resinous compositions have broad utility in many fieldsincluding use as coating and film-forming materials, adhesives, bindingagents, impregnating agents, molding compositions, laminating andcasting resins, and in reinforced plastic articles such as corrugatedand flat structural panels.

For a better understanding of the nature and objects of this invention,reference should be had to the accompanying illustrative exampleswherein all proportions are expressed in terms of weight unlessotherwise stated therein. Comparative examples are denoted by letterswhereas examples demonstrating the present invention are numbered.

Examples 1-12 Under an inert atmosphere of nitrogen in a suitable closedreaction vessel. propylene glycol, phthalic anhydride and maleicanhydride are reacted at reflux temperature in relative proportions of'2.'2':l.0:l.0 mols, respectively, until the acid number of the reactionmixture is between 35 and 40. After cooling the resulting unsaturatedlinear alkyd resin to room temperature, it is'thoroughly blended withstyrene in a weight ratio of 69:31, respectively, and 0.0115% ofhydroquinone based on the total weight of the mixture is dissolvedtherein toinhibit the composition against premature gelation. Theresulting liquid resin composition is divided into a, plurality ofbatches and the various additives listed in the table below areincorporated in separate batches of resin in the specified quantitiesbased on the total weight of liquid resin with thorough mixing. Then thegel time is determined with benzamidine hydrochloride and laurylmercaptan each present individually in some mixtures and as acombination in others, using benzoyl peroxide (BP), cumene hydroperoxide(CHP) and methyl ethyl ketone peroxide (MEKP) as the catalysts. Inaddition, a portion of each of these catalyzed resin compositions isemployed to laminate several plies of glass cloth which are cured in theusual manner and found to provide laminates having the same excellentphysical properties as a laminate prepared with the same resin with nopromoters therein.

Percent Percent Percent Ge] Time Example Lauryl Benzami- Catalyst at 25C.

Mercaptan dine H01 itEthylene guanidlue hydrochloride substituted forthe benzamidlne sa Example 13 Another polyester is prepared in a similarmanner from 3.3 mols of propylene glycol, 2 mols of phthalic anhydrideand 1 mol of maieic anhydride. A mixture is made of 62 parts of thisunsaturated alkyd resin,'38

parts of styrene, 0.0115 part of hydroquinone andqsufiicient cobaltnaphthenate to provide 0.32 part of; cobalt. This liquid resincomposition is divided into 4 portions, and an additional promotersystem in the form of 0.12% of laurylamidine hydrochloride and 0.12% ofthioglycolli i vw ac me ca tar s dded in e'ferm of solutions in dibutylphthalate. Then0.5%, based on the weight of total polymerizable matter,of tert butyl hydroperoxide s fi redin t atal e ech, o the ar ou batchesof resin. .01? the two batches containing'the amidine-mercaptan promotercombination one is cured at room temperature and the other at 180 F.;and while both batches gel within a matter of miputes, the one heated tothe elevated temperature Jgelsmuch more rapid- The comparative mp ewhicher tre o t e am dine-mercaptan p m system, ar v treated s m arlyand it is observed that the gelation takes much onger in both instancesand the batohmaiutained at room temperature fails to cure to a hardened,mass eyerrafterseveral days.

Example 1 resin is made up by .1 partof this polyester with An alkydresin is prepared by reacting 252 parts of propylene glycol, 296 partsof phthalic anhydride and 106 parts of fumaric acid at elevatedtemperature until the acid number is between 30 and 40. A mixture ismade of 62 parts of this polyester and 38 parts of styrene; then apromoter combination is added in the form of 0.5% of dicyclohexylguanidine and 1.0% of 2-rnercaptobenzoic acid as 20% solutions inethylene glycol. When this resin composition is catalyzed with 0.2% ofl-cyclohexanol-l-hydroperoxide, gelation rapidly takes place at roomtemperature in the gel test procedure. The cured casting displayed goodphysical properties and had an excellent appearance.

Example 16 Still another unsaturated alkyd resin is made by reacting 1.8molsof ethylene glycol, 1.5 mols of diethylene glycol, '2 mols of maleicanhydride and 1 mol of phthalic anhydride'inthe usual manner'and splitinto 2 equal portions of parts each. One of these batches is mixedthoroughly with '15 parts of diallyl phthalate, 0.008 part of'hydroquinone, 0.1 part of ethyl pseudothiourea hydrobromide and'0.1part of n-nonyl mercaptan' and later catalyzed with 0.5% by weight ofpinane hydroperoxide.

The other batch is compounded similarly except for omit-t ting themercaptan and'thiourea to serve as a control. It is found that gelationoccurs at F. in the S. P. I. test far more rapidly in the novel resincontaining the promoter system than in the control resin composition.

While there are above disclosed only a limited number of the embodimentsof the compositions and processes of the invention herein presented, itis possible to produce still other embodiments without departing fromthe inventive conceptherein disclosed, and it is desired, therefore,that only such limitations be imposed on the appended claims as arestated therein or required by the prior art.

We claim:

1. A composition of matter comprising 1) an unsaturated polyester resinprepared by reacting a polyhydric alcohol with an a, {3, ethylenicallyunsaturated polycarboxylic acid; (2) a monomer copolymerizable with said(1) and containing a CH =C group and having a boiling point of at least60 C.; (3) from about 0.001 to 1.0%, based on the combined Weight ofsaid (1) and (2), of a sulfhydryl compound and (4) from about 0.0003 to0.5%,"bas ed on the combined Weight of said (I) and (2), of a substanceselected from the group consisting of the guanidines, isomelamines,amidines, biguanides, guanylureas, pseudoure as, pseudothioureas and thesalts thereof.

2. A composition according to claim 1 in which said substance comprisesbenzamidine hydrochloride.

3. A composition according to claim 1 in which said substance comprisesethylene guanidine hydrochloride.

4. .A composition according .to claim 1 in which said substancecompriseslaurylamidine hydrochloride.

, 5. A composition according to claim 1 in which said substancecomprises 'dicyclohexyl guanidine.

6 .A composition according to claim 1 in which said substance comprisesethyl pseudothiourea hydrobromide.

-7. .A composition of matter comprising (1) an unsaturated polyesterresin prepared by reacting a .polyhydric alcohol with Ian .41, (B,ethylenically unsaturated polycarboxylic acid; (2) a. monomercopolymerizable with said 9 (1) and containing a CH =C group and havinga boiling point of at least 60 C.; (3) from about 0.001 to 1.0% of analkyl mercaptan, and from about 0.0003 to 5% of (4) benzamidinehydrochloride.

8. A composition according to claim 7 in which the alkyl mercaptancomprises lauryl mercaptan.

9. A composition of matter comprising (1) an unsaturated polyester resinprepared by reacting a polyhydric alcohol with an a, ,8, ethylenicallyunsaturated polycarboxylic acid; (2) a monomer copolymerizable with said(1) and containing a CH =C group and having a boiling point of at least60 C.; (3) from about 0.001 to 1.0% of an alkyl merca tan, and fromabout 0.0003 to 0.5% of (4) ethylene guanidine hydrochloride.

10. A process which comprises copolymerizing an unsaturated polyesterresin prepared by reacting a polyhydric alcohol with an a, ,8,ethylenically unsaturated polycarboxylic acid; and a monomer containinga CH =C group and having a boiling point of at least 60 C. in thepresence of an organic peroxide polymerization catalyst, from about0.001 to 1.0%, based on the combined weight of said polyester and saidmonomer, a sulfhydryl compound, and from about 0.0003 to 0.5%, based onthe combined weight of said polyester and said monomer, of a substanceselected from the group consisting of the guanidines, isomelamines,amidines, biguanides, guanylureas, pseudoureas, pseudothioureas and thesalts thereof.

11. A process according to claim 10 in which said substance comprisesbenzamidine hydrochloride.

12. A process according to claim 10 in which said substance comprisesethylene guanidine hydrochloride.

13. A process according to claim 10 in which said substance compriseslaurylamidine hydrochloride.

14. A process according to claim 10 in which said substance comprisesdicyclohexyl guanidine.

15. A process according to claim 10 in which said substance comprisesethyl pesudothiourea hydrobromide.

16. A process which comprises copolymerizing an unsaturated linearpolyester prepared by reacting a polyhydric alcohol with an a, 8,ethylenically unsaturated polycarboxylic acid with a monomer containinga CH =C group and having a boiling point of at least C. by reaction inadmixture with an organic peroxide polymerization catalyst, from about0.001 to 1.0 percent of an alkyl mercaptan and from about 0.0003 to 0.5percent of benzamidine hydrochloride based on the total weight of thepolyester and the monomer.

17. A process which comprises copolymerizing an unsaturated linearpolyester prepared by reacting a polyhydric alcohol with an 0L, 5,ethylenically unsaturated polycarboxylic acid with a monomer containinga CH =C group and having a boiling point of at least 60 C. by reactionin admixture with an organic peroxide polymerization catalyst, betweenabout 0.001 to 1.0 percent of an alkyl mercaptan and from about 0.0003to 0.5 percent of ethylene guanidine hydrochloride based on the totalweight of the polyester and the monomer.

Levine Nov. 2, 1948 Fisk Apr. 12, 1949

1. A COMPOSITION OF MATTER COMPRISING (1) AN UNSATURATED POLYESTER RESINPREPARED BY REACTING A POLYHYDRIC ALCOHOL WITH AN A, B, ETHYLENICALLYUNSATURATED POLYCARBOXYLIC ACID, (2) A MONOMER COPOLYMERIZABLE WITH SAID(1) AND CONTAINING A CH2=C< GROUP AND HAVING A BOILING POINT OF AT LEAST60*C., (3) FROM ABOUT 0.001 TO 1.0% BASED ON THE COMBINED WEIGHT OF SAID(1) AND (2), OF A SULFHYDRYL COMPOUND AND (4) FROM ABOUT 0.0003 TO 0.5%,BASED ON THE COMBINED WEIGHT OF SAID (1) AND (2), OF A SUBSTANCESELECTED FROM THE GROUP CONSISTING OF THE GUANIDINES, ISOMELAMINES,AMIDINES, BIGUANIDES, GUANYLUREAS, PSEUDOUREAS, PSEUDOTHIOUREAS AND THESALTS THEREOF.